Rotary gas compressor

ABSTRACT

A rotary gas compressor including a single vaned rotor positioned within a stator housing shaped to provide high and low pressure chambers, the housing and rotor being relatively movable to vary the sizes of the chambers. In one example, this construction can provide two-stage operation allowing the compressor to attain a high over-all pressure ratio. In a second example, the gas compressor is effective to provide high and low pressures to separate evaporators of a refrigeration system.

United States Patent [191 Newton 5] Aug. 14, 1973 [73] Assignee: Borg-Warner Corporation, Chicago,

Ill.

[22] Filed: Nov. 17, 1971 [21] Appl. No.: 199,551

[52] US. Cl 418/8, 418/13, 418/31 [51] Int. Cl...... F01c 1/30, FOlc 21/16, F04c 25/00 [58] Field of Search 418/8, 13, 24-27, 418/31; 62/510 [56] Reierences Cited UNITED STATES PATENTS 2,170,786 8/1939 McElroy et a1. 418/31 3,560,118 2/1971 Palachik 418/31 3,381,891 5/1968 Bellmer 418/13 2,481,605 9/1949 MacLeod 62/510 2,938,469 5/1960 Lauck 418/27 3,187,676 6/1965 Hartmann 418/31 FOREIGN PATENTS OR APPLICATIONS 374,348 4/1923 Germany 418/31 Primary Examiner-Carlton R. Croyle Assistant Examiner-John .l. Vrablik Attomey-T. B. Hunter [57] ABSTRACT A rotary gas compressor including; a single vaned rotor positioned within a stator housing shaped to provide high and low pressure chambers, the housing and rotor being relatively movable to vary the sizes of the charm bers. In one example, this construction can provide 4 Claims, 3 Drawing Figures ROTARY GAS COMPRESSOR This invention relates to gas compressors and more particularly to rotary gas compressors having a rotor and a stator housing therefor and providing relatively high and low compression chambers.

Conventional rotary gas compressors are used in re frigeration systems and comprise a single stage compressor housing a vaned rotor eccentrically mounted in a cylindrical stator housing and operative to compress refrigerant gas from an evaporator and to raise it to a high pressure in a single chamber of the housing for discharge to a condenser where the gas becomes liquified and transferred to the evaporator for return to its gaseous form. It will be apparent that the compressor is capable of service only with a single evaporator and condenser of a refrigeration system and of producing fixed and predetermined gas compression value and is incapable of varying this value.

The rotary gas compressor of the present invention is characterized by providing a stator housing designed and cooperating with a vaned rotor to provide high and low pressure chambers, the chambers sizes being variable by movement of the housing relative to the rotor. This construction and arrangement of my improved gas compressor is capable, in one example, of providing a two-stage operation permitting the compressor to provide a higher over-all pressure ratio, the refrigerant gas, entering a first chamber of the compressor, being compressed in approximately 90 of rotor rotation, and then entering a second chamber of smaller size than the first chamber wherein it is again compressed in 90 of rotor rotation and then is discharged from the compressor. In a second example of usage, the gas compressor may have its two chambers connected to separate evaporators, the relative capacity of chambers being varied by movement of the stator housing and the rotor being effective to simultaneously compress gas entering respective chambers and to discharge it from the chambers.

It is therefore a principal object of the invention to provide an improved rotary gas compressor.

Another object of the invention is to provide an improved rotary gas compressor having a rotor and stator housing constructed and arranged to provide relatively high and low pressure chambers.

Another object of the invention is to provide an improved rotary gas compressor in which the rotor and stator housing define high and low pressure chambers and are relatively movable to vary the pressures in the chambers.

Another object of the invention is to provide an improved rotary gas compressor having a rotor and stator housing therefor providing high and low pressure chambers connected to each other to provide two-stage operation of the compressor.

Additional objects and advantages will be apparent from the following detailed description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an improved rotary gas compressor of a preferred embodiment of the invention and illustrating its usage in a two-stage operation.

FIG. 2 is a cross-sectional view taken along the plane of line 2--2 of FIG/1; and

FIG. 3 is a cross-sectional view of the improved gas compressor illustrating its usage with dual refrigeration systems.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, the gas compressor 10 utilizing the principles of the present invention comprises a casing 11, a stator 12, and. a rotor assembly 13. The casing 11 includes a generally rectangular chamber 14 (FIG. 2) containing the stator 12 and having a side wall 15 bored as at 16 to provide a cylindrical opening having a bearing 17, a bearing plate 18 forming the other opposite side wall of the casing, the bearing plate 18 and bearing 17 rotatably mounting the rotor assembly 13 within the stator 12. The bearing plate 18 closes the open end of the housing 11 and is secured thereto by screws, as shown in FIG. 1.

The rotor assembly 13 includes a cylindrical rotor element 19 having a plurality of radially extending slots 20 each of which are adapted to receive a vane member 21 reciprocable therein. Rotor element 19 is keyed at 22 to a drive shaft 23 journaled in the anti-friction bearing 17 supported by casing wall 15 and an antifriction bearing 24 supported within a counterbore in the bearing plate 18. The compressor rotor assembly is driven by a V-belt pulley 25 drivingly connected to the rotor drive shaft 23.

The rotor assembly is rotatable within the stator 12 and which serves as a housing for the rotor assembly. The stator 12 is mounted in the casing 11 for vertical movement relative to the rotor assembly. More particularly, the stator 12 is in the form of a shiftable ring 26 equal in width to that of the rotor element 19 as shown in FIG. 1. The ring 26 is provided with parallel flat slides 27 and 28 on its external annular surface, the slides being diametrically opposed from each other. The slides 27 and 28 of the ring 26 engage the flat inter nal surfaces 29 and 30 of the end walls 31 and 32 of the casing 11 whereby the stator may be movable vertically of the casing and relative to the rotor assembly 13.

As seen in FIG. 2, the stator ring 26 has a generally elliptical-shaped inner surface comprised of upper and lower reversely curved arcuate faces 33 and 34 connected at their ends by flat faces 35 and 36 respectively merging with the faces 33 and 34, the faces 35 and 36 being parallel to the faces 29 and 30 of the casing 1 l. The radius of curvature of the face 33, and also of the face 34, is approximately equal to the radius of curvature of the cylindrical surface 37 of the rotor element 19. i

As shown in FIG. 2, the elliptical inner surface of the stator 12 spaces the curved faces 33 and 34 thereof from the rotor element to provide spaced upper and lower gas compression chambers 38 and 39. It may be noted that the distance between the flat faces 35 and 36 of the stator ring 26 is approximately equal to the diameter of the rotor element to provide engagement of the stator faces 35 and 36 with the cylindrical surface 37 of the rotor to provide cut-off points to prevent the passage of the compressed gas in the chamber 38 to the chamber 39 and also to preclude the flow of compressed gas in the chamber 39 into the chamber 38 by the action of the vanes 21 during rotation of the rotor element.

The stator ring 26 is shiftable vertically of the casing l l and rotor assembly 13 by positioning elements in the form of a screw 41 threaded into the bottom wall 42 of the casing 11 and engaging the stator ring 26 to position it within the casing 11 along the surfaces 29 and 30 of the casing 11. A compression spring 43 is positioned within an opening in the top wall 44 of the easing 11 and is confined therein to bear against the ring 26 by a screw threaded into the casing 11. The screw 41 is adjustable to move the stator ring vertically within the casing and relative to the rotor assembly to any desired location from its position shown in FIGS. 1 and 2, wherein the chamber 39 is slightly larger than the chamber 38, to simultaneously increase the size of one of the chambers 38 or 39 while decreasing the size of the other chamber 38 or 39.

FIG. 2 is somewhat schematic in illustrating the construction of the casing 11 and stator 12 for providing for the passage of gas to and through the compressor. As shown, gas flows into the inlet passage 45 in the casing 11 and through the connecting suction port 46 in the stator ring 26 into the chamber 39. Since the rotor element is rotating, the vanes 21 are caused to reciprocate in the slots 20 in the rotor element. It may be noted that the vanes are arranged so that their radially outermost or tip portions are in constant engagement with the generally elliptically shaped inner surface of the stator 12, and that, oil for lubricating and sealing purposes is supplied to the space underneath each vane by means of grooves 47 cut into the back face of the rotor element, the oil pressure also serving to hold the vanes outwardly against the inner surface of the stator. Upon rotation of the rotor element in the direction shown and reciprocation of the vanes, the vanes will compress the gas in chamber 39 and cause the compressed gas to flow through the discharge port 48 in the stator ring 26and the outlet passage 49 of the casing 11. Simultaneously, gas can flow into an inlet passage 50 in the casing 11 and a connected suction port 51 in the stator ring 26, and into the chamber 38 where it will be compressed by the vanes, the compressed gas then flowing through discharge port 52 in the stator ring and outlet passage 53 in the casing 11.

In its preferred embodiment of the compressor shown in FIGS. 1 and 2, the gas compressor is utilized to provide a two-stage operation in which a refrigerant gas stream, entering the chamber 39 of the compressor, is compressed in approximately 90 of rotor rotation, and then enters the smaller chamber 38 of the compressor wherein it is again compressed in 90 of rotor rotation and discharged from the compressor. More particularly and referring to FIG. 2, in the described operation of the compressor, the compressed gas, flowing from the compressors large chamber 39, is discharged through port 48 and passage 49 into a conduit 54, which may be connected to an intercooler 55 through which the gas flows into a conduit 56 directing the compressed gas into the passage 50 and port for flow into the smaller chamber 38 of the compressor, where the gas is'further compressed and flows through the discharge port 52 and passage 53. The intercooler may be cooled by any means such as direct contact with liquid refrigerant expanded to intermediate pressure, or by cooling means external to the cycle. It will be apparent that the compressor thus provides for the two-stage operation of a single rotor, and, by movement of its stator housing, the relative sizes of the high and low pressure chambers of the compressor can be varied for gas compression; whereby the compressor is allowed to attain a high over-all pressure ratio.

FIG. 3 illustrates the gas compressor in its usage in an alternate arrangement in which it is employed with dual refrigeration systems. More particularly, the gas compression chambers 38 and 39 of the compressor may be connected to two separate conventional refrigeration systems and serve their evaporators, their relative capacities being varied by screw 41. In FIG. 3, gas can flow from the evaporator 60 through conduit 61 and inlet passage 45 and suction port 46 into the chamber 39 where it is compressed and exits from the compressor through discharge port 48 and outlet passage 49 into conduit 62 connected to the condenser 63. Simultaneously, rotation of rotor 19 causes gas, entering inlet passage 50 and port 51 via conduit 64 from the evaporator 65, to be compressed in chamber 38 and discharged through port 52 and passage 53 into the conduit 66 connected to the condenser 67.

In the event it should be desired to employ two evaporators in one assembly for a dual purpose, such as disclosed in US. Pat. No. 2,195,781 issued Apr. 2, 1940, the compressor of the present invention can cool one evaporator while the other may be converted for use as a condenser for reheat. In this arrangement, the relative capacities can also be adjustable by movement of the screw 41.

What is claimed is:

l. 'A compressor comprising a generally cylindrical rotor, said rotor being provided with a plurality of generally radially extending, slidable vanes; a rotor housing surrounding said rotor having a generally elliptically shaped chamber, the inner surface of which is engaged by said vanes, said rotor being located within said chamber so as to be closely adjacent said inner surface at two oppositely disposed points to provide first and second crescent-shaped compression cavities on opposite sides of said rotor; means defining a pair of suction ports respectively communicating with said compression cavities; means defining a pair of discharge ports respectively communicating with said compression cavities; means for interconnecting the discharge port of one compression cavity to the suction port of the other compression cavity; and pressureratio control means for simultaneously reducing the volume of said first compression cavity and increasing the volume of said second compression cavity.

2. A compressor as defined in claim 1 in which said pressure ratio control means comprises means for moving said housing relative to said rotor.

face of said rotor. 

1. A compressor comprising a generally cylindrical rotor, said rotor being provided with a plurality of generally radially extending, slidable vanes; a rotor housing surrounding said rotor having a generally elliptically shaped chamber, the inner surface of which is engaged by said vanes, said rotor being located within said chamber so as to be closely adjacent said inner surface at two oppositely disposed points to provide first and second crescent-shaped compression cavities on opposite sides of said rotor; means defining a pair of suction ports respectively communicating with said compression cavities; means defining a pair of discharge ports respectively communicating with said compression cavities; means for interconnecting the discharge port of one compression cavity to the suction port of the other compression cavity; and pressure ratio control means for simultaneously reducing the volume of said first compression cavity and increasing the volume of said second compression cavity.
 2. A compressor as defined in claim 1 in which said pressure ratio control means comprises means for moving said housing relative to said rotor.
 3. A compressor as defined in claim 2 in which said rotor housing inner surface has spaced parallel flat faces, and said rotor has engagement, at diametrically spaced portions thereof, with said faces to provide cut-off points defining said chambers.
 4. A compressor as defined in claim 3 in which said elliptically shaped chamber has spaced reversely curved arcuate faces connected by said flat faces of said housing surface, each arcuate face having a radius of curvature approximately equal to the cylindrical surface of said rotor. 